Air conditioning system

ABSTRACT

An air-conditioning system including an air-conditioning apparatus having a compressor circulating a refrigerant, and an outdoor unit and an indoor unit performing air conditioning of an air-conditioned room; outside air introduction means supplying air outside the air-conditioned room; outside air temperature detection means detecting a temperature outside the air-conditioned room; human body position detection means detecting a user in the air-conditioned room; target-room-temperature determination means determining a user number and/or a variation of the user number in the air-conditioned room on the basis of the detection of the human body position detection means and determining a target room temperature; and cooling-operation-method determination means determining whether to operate the air-conditioning apparatus or to operate the outside air introduction means on the basis of the target room temperature and the temperature outside the air-conditioned room.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an air conditioning system that airconditions an air-conditioned space.

2. Description of the Related Art

In the related art, there is an air conditioning system that performs acooling/heating operation so that a comfortable temperature is reachedwhen a motion sensor detects presence of an occupant in a room and thatperforms a low load operation when the motion sensor detects no occupantin the room (see Patent Literature 1, for example). Further, when atemperature of air (outside air) of a non-air-conditioned space(outdoor) is lower than a temperature of an air-conditioned space, atypical outside air cooling operation performs a cooling operation, forexample, by suspending an operation of a compressor in order to stop anoperation performed with a refrigerant circuit and by introducing theoutside air into the conditioned space.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Unexamined Patent Application PublicationNo. 11-006644 (FIG. 1)

BRIEF SUMMERY OF THE INVENTION Technical Problem

A known air conditioning system, such as the one in Patent Literature 1,is capable of performing energy saving operations while there is nooccupant in a room; however, when there is an occupant in the room,operation is performed with a fixed target room temperature.

Here, a comfortable temperature for an occupant who has entered the roomfrom a hot outdoor area and a comfortable temperature for an occupantwho has been in the room for a long time and is sufficiently cooled are,in most cases, different. If the target room temperature is set low tosuit the occupant who has entered the room, it will be cold for theoccupant who has been in the room and it will cause energy to be lostdue to over cooling. Whereas, if the target room temperature is sethigh, it will be hot for the former occupant, disadvantageouslyimpairing comfortability.

Further, although the outside air cooling operation does not require theoperation of the refrigerant circuit in which the compressor is driven,when the outside air temperature is relatively high without muchdifference with the target room temperature, a large amount of outsideair needs to be introduced (supplied). Accordingly, conveyance power forthe outside air increases, resulting in increase of power consumption;hence, energy saving is disadvantageously hindered. In particular, ifthe outside air is introduced through a long duct, the conveyance powerloss is increased markedly. Further, when the outside air temperature isexcessively low, the outside air cooling operation cannot be performeddue to possibility of dew condensation and the like. Accordingly, therange of the outside air temperature allowing performance of the outsideair cooling operation is limited; hence, sufficient advantages are notobtained throughout the year.

The invention addresses to the above disadvantages and an object thereofis to provide an air conditioning system that is capable of achievingenergy saving while maintaining a temperature corresponding to a stateof the occupants in an air-conditioned space.

Solution to Problem

An air-conditioning system of the invention includes an air-conditioningapparatus that has a compressor that circulates a refrigerant and thatperforms air conditioning of an air-conditioned space; a fan thatsupplies air outside the air-conditioned space; outside air temperaturedetection means that detects a temperature outside the air-conditionedspace; heat source detection means that detects a heat source object inthe air-conditioned space;

target-room-temperature determination means that determines a usernumber and/or a variation of the user number in the air-conditionedspace on the basis of a detection of the heat source detection means andthat determines a target room temperature that is a temperature targetof the air-conditioned space; and cooling-operation-method determinationmeans that determines whether to operate the air-conditioning apparatusor to operate the fan on the basis of the target room temperature andthe temperature outside the air-conditioned space.

Advantageous Effects of Invention

According to the invention, an energy saving operation using the outsideair can be performed while maintaining the temperature to a temperaturecorresponding to the state of the occupants in the air-conditioned spaceby determining the target room temperature on the basis of the number ofoccupants in the air-conditioned space and variation of the numberthereof and by determining whether to operate the air-conditioningapparatus or the fan on the basis of the target room temperature and thelike.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating an air-conditioning systemaccording to Embodiment 1 of the invention;

FIG. 2 is a block diagram illustrating an air-conditioning apparatusaccording to Embodiment 1 of the invention;

FIG. 3 is a diagram illustrating a relationship between users of anair-conditioned room and a detection signal of human body positiondetection means according to Embodiment 1 of the invention;

FIG. 4 is a diagram illustrating a flowchart of a procedure that isperformed by target-room-temperature determination means according toEmbodiment 1 of the invention;

FIG. 5 is a diagram illustrating power consumed when outside airintroduction means is driven and when a refrigerant circuit is operated;

FIG. 6 is a diagram related to a process of cooling-operation-methoddetermination means according to Embodiment 1 of the invention and is adiagram illustrating the relationship between the cooling operation,when the level of the occupant number is high or when the level has beenincreased, and the outside air temperature;

FIG. 7 is a diagram related to the process of thecooling-operation-method determination means according to Embodiment 1of the invention and is a diagram illustrating the relationship betweenthe cooling operation, when the level of the occupant number is low,intermediate, or zero, or when the level has been decreased or there hasbeen no change, and the outside air temperature;

FIG. 8 is a schematic diagram illustrating an air-conditioning systemaccording to Embodiment 3 of the invention; and

FIG. 9 is a diagram illustrating a flowchart of a procedure that isperformed by the cooling-operation-method determination means accordingto Embodiment 3 of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Subsequently, Embodiments of the invention will be described withreference to the drawings. Note that the configuration, the operation,and the like of the air conditioning system of the invention are notlimited to those that are described in the subsequent Embodiments.

Embodiment 1

FIG. 1 is a schematic diagram illustrating an air-conditioning systemaccording to Embodiment 1 of the invention. Referring to FIG. 1, the airconditioning system of Embodiment 1 includes an air-conditioningapparatus having an outdoor unit 1 and an indoor unit 3 connected byrefrigerant pipes 2. The indoor unit 3 is disposed in an air-conditionedroom 4. Further, the air-conditioned room 4 is provided with outside airintroduction means 6 such as a fan, an outside air introduction duct 7,human body position detection means (human body position detectionsensor) 5, and room temperature detection means (room temperaturedetection sensor) 9. Furthermore, outside air temperature detectionmeans (outside air temperature detection sensor) 10 and a controller 11are provided outside the air-conditioned room 4.

FIG. 2 is a block diagram illustrating the air-conditioning apparatusaccording to Embodiment 1 of the invention. The air-conditioningapparatus includes a refrigerant circuit, which circulates a refrigerantbetween the outdoor unit 1 and the indoor unit 3, and performs airconditioning of the air-conditioned room 4. In Embodiment 1, descriptionis given assuming that air conditioning is performed with a coolingoperation that cools the air-conditioned room 4. As illustrated in FIG.2, the outdoor unit 1 of Embodiment 1 includes various devices (means)such as a compressor 101, a four-way valve 102, an outdoor side heatexchanger 103, and an outdoor side fan 104.

The compressor 101 compresses and discharges the suction refrigerant.Further, the outdoor side heat exchanger 103 exchanges heat between therefrigerant and air (outdoor air). Here, the outdoor side heat exchanger103 of Embodiment 1 functions, for example, as an evaporator during aheating operation; exchanges heat between a low-pressure refrigerant,which has flowed therein from the refrigerant pipe 2, and the air; andevaporates and gasifies the refrigerant. Further, the outdoor side heatexchanger 103 functions as a condenser during a cooling operation;exchanges heat between a refrigerant, which has flowed from the four-wayvalve 102 side and that has been compressed in the compressor 101, andair; and condenses and liquefies the refrigerant. Furthermore, theoutdoor side fan 104 sends in air from the outside of theair-conditioned room 4 so that efficient heat exchange is performedbetween the refrigerant and the air. The four-way valve 102 switches theflow of the refrigerant between a flow for a cooling operation and aflow for a heating operation in accordance with an instruction from thecontroller 11.

Meanwhile, the indoor unit 3 includes an indoor side heat exchanger 301,and indoor side expansion device (expansion valve) 302, and an indoorside fan 303. The indoor side heat exchanger 301 exchanges heat betweenthe refrigerant and the air in the air-conditioned room 4. The indoorside heat exchanger 301 functions, for example, as a condenser during aheating operation; exchanges heat between the refrigerant, which hasflowed therein from the refrigerant pipe 2, and the air; condenses andliquefies (or into a two-phase gas-liquid state) the refrigerant, andmakes the refrigerant flow out therefrom. The indoor side heat exchanger301 functions as an evaporator during a cooling operation; exchangesheat between the refrigerant, which has been turned into a low-pressurestate with the indoor side expansion device 302, and the air; evaporatesand gasifies the refrigerant by having the refrigerant remove heat fromthe air; and makes the refrigerant flow out therefrom. Further, theindoor unit 3 is provided with the indoor side fan 303 to control theflow of air that performs heat exchange.

The human body position detection means 5 serving as a heat sourcesensor is, for example, an infrared sensor. For example, the human bodyposition detection means 5 scans the entire air-conditioned room 4,detects a two-dimensional temperature distribution of the entireair-conditioned room 4, and transmits a signal to the controller 11.Here, although the human body position detection means 5 scans anddetects the two-dimensional temperature distribution of the entireair-conditioned room 4, the invention is not limited to this. Forexample, an array of infrared sensors may constitute the human bodyposition detection means 5 such that detection of the two-dimensionaltemperature distribution of the entire air-conditioned room 4 is carriedout without any scanning.

The room temperature detection means 9 that serves as an indoor airtemperature sensor detects the air temperature in the air-conditionedroom 4 and transmits a signal to the controller 11. Further, the outsideair temperature detection means 10 that serves as an outside airtemperature sensor detects the air (outside air) temperature (outsideair temperature) outside the air-conditioned room 4 and transmits asignal to the controller 11.

The outside air introduction means 6 includes a fan, drives the fan, andsends outside air into the air-conditioned room 4 from the outside ofthe air-conditioned room 4 through the outside air introduction duct 7.

Each signal line 8 is a line for communicating with the controller 11.Here, in Embodiment 1, a signal line 8 a is a line for transmitting asignal related to a detection of the outside air temperature detectionmeans 10. A signal line 8 b is a line for communicating between theindoor unit 3 and the controller 11. A signal line 8 c is a line fortransmitting a signal related to a detection of the room temperaturedetection means 9. A signal line 8 d is a line for transmitting a signalrelated to a detection of the human body position detection means 5. Asignal line 8 e is a line for communicating between the outside airintroduction means 6 and the controller 11.

The controller 11 controls each of the components of the airconditioning system. In Embodiment 1, the controller 11 includestarget-room-temperature determination means 12 andcooling-operation-method determination means 13. Thetarget-room-temperature determination means 12 performs a determinationprocess of the target room temperature in the air-conditioned room 4 incorrespondence with the signal sent from the human body positiondetection means 5. Details of the process will be described below.Further, the cooling-operation-method determination means 13 performs adetermination process of whether to perform a cooling operation with theair-conditioning apparatus (refrigerant circuit) or to perform anoutside air cooling operation that makes the outside air flow into theair-conditioned room 4 from the outside air introduction means 6 on thebasis of the target room temperature that the target-room-temperaturedetermination means 12 has determined and the outside air temperaturerelated to the detection of the outside air temperature detection means10. Furthermore, the operation of each component is controlled such thatthe room temperature related to the detection of the room temperaturedetection means 9 becomes a target room temperature that thetarget-room-temperature determination means 12 has determined.

FIG. 3 is a diagram illustrating relationships between users 20 (20 a,20 b, 20 c, 20 d) of the air-conditioned room 4 and detection signals ofthe human body position detection means 5 according to Embodiment 1 ofthe invention. Referring first to FIG. 3( a), a case in which no user 20is present in the air-conditioned room 4 will be described. When thereis no user 20, the signal strength of a vertically oriented outputsignal 21, which is a signal in the vertical direction (heightdirection) of the air-conditioned room, remains at zero (level zero) asshown with a vertically oriented output signal 21 a. Further, as for ahorizontally oriented output signal 22 in the horizontal direction ofthe air-conditioned room 4, the signal strength remains at zero, asshown with a horizontally oriented output signal 22 a.

Referring next to FIG. 3( b), a case in which users 20 are present inthe air-conditioned room 4 will be described. As illustrated in FIG. 3(b), there are three users, namely, user 20 b, user 20 c, and user 20 d,in the air-conditioned room 4, for example. At this time, a verticallyoriented output signal 21 b has three high-signal-level portions wherethe signal strengths are strong, each corresponding to the height of theusers 20 b, 20 c, and 20 d, respectively. Further, a horizontallyoriented output signal 22 b also has three portions where the signallevels are high, each corresponding to the positions of the users 20 b,20 c, and 20 d, respectively. Note that either one of the verticallyoriented output signal 21 and the horizontally oriented output signal 22may detect the user 20. In Embodiment 1, the human body positiondetection means 5 is provided in the ceiling of the air-conditioned room4. The human body position detection means 5 transmits the horizontallyoriented output signal 22 b to the controller 11.

FIG. 4 is a diagram illustrating a flowchart of a procedure that isperformed by the target-room-temperature determination means 12according to Embodiment 1 of the invention. Referring to FIG. 4, theprocess of the target-room-temperature determination means 12 will bedescribed. Here, the target-room-temperature determination means 12presets and stores threshold values that are needed to perform thedetermination and the like as initial values. For example, the level ofoccupant number in the air-conditioned room 4 is set. Here, the level ofoccupant number is set to three levels, namely, low, intermediate, andhigh. Further, as boundary values of the total area of the heat sourceobject, area 1 and area 2 each serving as a predetermined area value isset. Here, the total heat-source-object area is determined on the basisof the summation of the high-signal-level portions of the horizontallyoriented output signal 22 b illustrated in FIG. 3.

Further, in Embodiment 1, the target room temperature is set to a targetroom temperature for large occupant number when the level of occupantnumber is high or when the level of occupant number has increased fromthe preceding determination. Furthermore, the target room temperature isset to a target room temperature for small occupant number when thelevel of occupant number is low, intermediate, or zero, as well as whenthe level of occupant number has decreased or has not changed.

First, in step 1, the temperature distribution of the entireair-conditioned room 4 is determined on the basis of the signaltransmitted from the human body position detection means 5. Further, instep 2, the total area (total heat-source-object area) of the heatsource object (user 20) is calculated on the basis of the temperaturedistribution.

Next, in step 3, the level of occupant number is determined by comparingthe total heat-source-object area and the aforementioned boundaryvalues. For example,

-   -   when total heat-source-object area=0, then the level of occupant        number is determined to be zero;    -   when 0<total heat-source-object area<area 1, then the level of        occupant number is determined to be low;    -   when area 1≦total heat-source-object area<area 2, then the level        of occupant number is determined to be intermediate; and    -   when 2≦total heat-source-object area, then the level of occupant        number is determined to be high.

In step 4, it is determined whether the level of occupant number is highon the basis of the determination result. When it is determined to behigh, step 6 is processed. When it is determined to be not high (thelevel of occupant number is zero, low, or intermediate), step 5 isprocessed. Further, in step 5, it is determined whether the level ofoccupant number has increased from the preceding determination (scan).When it is determined that the level of occupant number has increased,step 6 is processed. When it is determined that the level of occupantnumber has not increased (decrease in level or no change), step 7 isprocessed. Here, increase in the level of occupant number refers to sucha case where the preceding level of occupant number that had beendetermined to be zero is determined to be low, intermediate, or high,for example. Further, there is a case where the preceding level ofoccupant number that had been determined to be low is determined to beintermediate or high. Furthermore, there is a case where the precedinglevel of occupant number that had been determined to be intermediate isdetermined to be high.

After the target room temperature for large occupant number, which hasbeen set when the level of occupant number is high or when the level ofoccupant number has increased, is determined as the target roomtemperature in step 6, the process returns to step 1. On the other hand,after the target room temperature for small occupant number—having beenset when the level of occupant number is low, intermediate, or zero, orwhen the level of occupant number has decreased or has not changed—isdetermined as the target room temperature in step 7, the process returnsto step 1. The target-room-temperature determination means 12 determinesthe target room temperature in the air-conditioned room 4 by performingthe above process.

Here, the cooling capacity of the outside air that is introduced intothe air-conditioned room 4 by the outside air introduction means 6 canbe expressed by the following equation (1). As in equation (1), thecooling capacity can be expressed as a function F1 that is a valueobtained by multiplying the air volume to the temperature differencebetween the target room temperature and the outside air temperature. Itcan be understood from equation (1) that when the temperature differencebetween the target room temperature and the outside air temperature issmall, larger air volume is required to obtain the same coolingcapacity.

Cooling capacity=F1(air volume×(target room temperature−outside airtemperature))   (1)

Further, power consumption of the outside air introduction means 6 canbe expressed by the following equation (2). As in equation (2), thepower consumption of the outside air introduction means 6 can beexpressed as a function F2 of the air volume. Accordingly, it can beunderstood that power consumption increases when air volume isincreased.

Power consumption of the fan=F2 (air volume)   (2)

FIG. 5 is a diagram illustrating power consumed when the outside airintroduction means 6 is driven and when the air-conditioning apparatusis operated. Referring to FIG. 5, the axis of ordinates represents thepower consumption, and the axis of abscissas represents the air volumeof the outside air introduction means 6. Line 31, representing the powerconsumption of the outside air introduction means 6 while in operation,shows that the power consumption increases when the air volume of theoutside air introduction means 6 increases. On the other hand, Line 32represents the power consumption of the air-conditioning apparatus(refrigerant circuit) while in operation. The power consumption ismainly that of the driven compressor 101 although it including the powerconsumption of the driven outdoor side fan 104. As shown in FIG. 5, thepower consumption of the air-conditioning apparatus while in operationis substantially constant irrespective of the air volume of the outsideair introduction means 6. Further, FIG. 5 shows that the powerconsumption is lower when the outside air introduction means 6 isoperated in the region on the left side of the intersection pointbetween line 31 and line 32 and the power consumption is higher when theoutside air introduction means 6 is operated in the region on the rightside of the intersection point.

FIG. 6 is a diagram related to the process of thecooling-operation-method determination means 13 according to Embodiment1 of the invention and is a diagram illustrating the relationshipbetween the cooling operation, when the level of the occupant number ishigh or when the level has been increased, and the outside airtemperature. Here, as an example, the target room temperature determinedby the target-room-temperature determination means 12 is set to thetarget room temperature for large occupant number (22° C.). Further,each of T1, T2, T3, T4, and T5 represents a temperature range of theoutside air temperature. Here, T1 is the lowest temperature range. Thetemperature range becomes higher in the order of T2, T3, and T4, and T5is the highest temperature range. Here, the temperature within thetemperature range T4 is lower than the target room temperature, and thetemperature within the temperature range T5 is higher than the targetroom temperature.

For example, when outside air with a temperature within the lowesttemperature range T1 is introduced into the air-conditioned room 4,there is a possibility of dew condensation caused by increase in therelative humidity of air in the area where the air in theair-conditioned room 4 is cooled by mixing of the air in theair-conditioned room and the outside air. Accordingly, there is apossibility of dew condensation water that has occurred near the airoutlet of the outside air introduction duct 7 flowing into theair-conditioned room 4; hence, outside air cooling operation cannot beperformed. For example, in a case where the temperature in theair-conditioned room 4 is higher than the target room temperature due toheat emitted from heat sources such as OA equipment and the like, evenif the outside air temperature is low, a cooling operation with theair-conditioning apparatus is performed.

Further, when the temperature of outside air is within the temperaturerange T2, which is a temperature that is in the low temperature regionbut has no risk of dew condensation, cooling effect can be obtained byintroducing outside air with a small volume, that is, with a small airvolume (introduction volume of outside air), into the air-conditionedroom 4. Further, when the temperature of outside air is within thetemperature range T3, which is a temperature that is a little higherthan that of the temperature range T2, the temperature differencebetween the target room temperature is smaller compared to that of theoutside air in the temperature range T2. Accordingly, based on theaforementioned equation (1), a cooling effect can be obtained byintroducing outside air with an intermediate air volume, which has moreair volume than the small air volume, into the air-conditioned room 4.

Furthermore, when the temperature of outside air is within thetemperature range T4, which is a temperature that is a little higherthan that of the temperature range T3, the temperature differencebetween the target room temperature is smaller still compared to that ofthe outside air in the temperature range T3. The air volume may befurther increased to maintain the cooling capacity; however, as shown inFIG. 5, if the power consumed in the operation of the outside airintroduction means 6 exceeds the power consumed by the operation of theair-conditioning apparatus, then the cooling operation with theair-conditioning apparatus will be more energy saving. Accordingly, thecompressor 101 is driven and cooling operation is performed with theair-conditioning apparatus when the outside air temperature is withinthe temperature range T4. When the outside air temperature is within thehighest temperature range T5, it will not be possible to perform coolingthat introduces outside air since the outside air will heat the air inthe air-conditioned room 4. Accordingly, the compressor 101 is drivenand a cooling operation with the air-conditioning apparatus isperformed.

FIG. 7 is a diagram related to the process of thecooling-operation-method determination means 13 according to Embodiment1 of the invention and is a diagram illustrating the relationshipbetween the cooling operation—when the level of the occupant number islow, intermediate, or zero, or when the level has been decreased orthere has been no change—and the outside air temperature. Here, as anexample, the target room temperature determined by thetarget-room-temperature determination means 12 is set to the target roomtemperature for small occupant number (25° C.). The relationshipsbetween T1 to T5 are the same as FIG. 6.

Since the target room temperature is set high, the cooling capacity canbe small. Accordingly, as regards the outside air with a temperature inthe temperature ranges T2, T3, and T4, for example, if the temperaturedifference between the target room temperature and the outside airtemperature is the same, from the aforementioned equation (1), the airvolume of the fan of the outside air introduction means can be small.For example, in comparison with FIG. 6, when the outside air temperatureis a temperature in the temperature range T2, the temperature differencebecomes larger than that of FIG. 6, and a cooling effect can be obtainedby introducing outside air with a minute air volume into theair-conditioned room 4 rather than a small air volume. Further, also inthe case in which the outside air temperature is a temperature in thetemperature range T3, since the temperature difference is large, acooling effect can be obtained by introducing outside air with a smallair volume into the air-conditioned room 4 rather than an intermediateair volume. Furthermore, when the outside air temperature is atemperature in the temperature range T4, operation of theair-conditioning apparatus is performed in FIG. 6; however, in FIG. 7,outside air cooling operation can be performed since the operation ofthe outside air introduction means 6 consumes smaller power than thedriving of the compressor 101 and the operation of the air-conditioningapparatus.

As above, according to the air conditioning system of Embodiment 1,since the target-room-temperature determination means 12 determines thetarget room temperature on the basis of the number of users in theair-conditioned room 4 and the variation of the number thereof, andsince the cooling-operation-method determination means 13 determineswhether to operate the outdoor unit 1 and the indoor unit 3 or tooperate the outside air introduction means 6 on the basis of the targetroom temperature and the outside air temperature, an energy savingoperation using the outside air can be performed while maintaining thetemperature to a temperature corresponding to the state of the user(s)20 in the air-conditioned room 4.

Embodiment 2

In the above-mentioned Embodiment 1, the target-room-temperaturedetermination means 12 determines the target room temperature from thetwo, the target room temperature for large occupant number and thetarget room temperature for small occupant number; however, theinvention is not limited to the above. For example, the target roomtemperature may be determined from among three or more set target roomtemperatures, on the basis of the signal of the human body positiondetection means 5.

Embodiment 3

FIG. 8 is a schematic diagram illustrating an air-conditioning systemaccording to Embodiment 3 of the invention. Referring to FIG. 8,components and the like attached with like reference numerals servessimilar roles as that in Embodiment 1. As illustrated in FIG. 8, thecooling-operation-method determination means 13 includes powerconsumption determination means 16. The power consumption determinationmeans 16 determines the power consumption of the compressor 101 on thebasis of the refrigerant discharge pressure and the dischargetemperature of the compressor 101, the rotation speed of the compressor101, and the like. Further, the power consumption determination means 16determines the power consumption of the outside air introduction means6. Thus, the power consumption determination means 16 has tabular data,for example, that shows the relationship between the power consumptionand the discharge pressure of the refrigerant, the discharge temperatureof the refrigerant, the rotation speed of the compressor 101, and thelike. Similarly, the power consumption determination means 16 hastabular data, for example, that shows the relationship between the powerconsumption and the air volume, the rotation speed, and the like of theoutside air introduction means 6.

FIG. 9 is a diagram illustrating a flowchart of a procedure that isperformed by the cooling-operation-method determination means 13according to Embodiment 3 of the invention. The processing operation ofthe cooling-operation-method determination means 13 provided with thepower consumption determination means 16 will be described withreference to FIG. 9.

In step 20, it is determined whether the compressor 101 is driven(whether the air-conditioning apparatus is in operation). When it isdetermined that the compressor 101 is being driven, the process proceedsto step 21. When it is determined that the compressor 101 is not beingdriven, the process proceeds to step 26. In step 21, the currentrefrigerant discharge pressure and the current refrigerant dischargetemperature of the compressor 101 and the current rotation speed of thecompressor 101 is measured. For the measurement, pressure detectionmeans, temperature detection means, and the like are disposed in thedischarge side pipe or the like. Further, in step 22, the powerconsumption determination means 16 determines the current powerconsumption of the air-conditioning apparatus (mainly the compressor101) on the basis of the aforementioned data. In this example, the powerconsumed by the air-conditioning apparatus is determined on the basis ofboth data associated with the compressor 101 which consumes majority ofthe power and a fixed value or values added for the other components;however, its determination may be performed by including the powerconsumption obtained by measuring or the like the power consumption ofthe other components, such as the outdoor side fan 104.

In step 23, the air volume and the rotation speed of the outside airintroduction means 6, which are required in order to obtain the coolingcapacity during the outside air cooling operation, are calculated anddetermined on the basis of the temperature difference between thecurrent outside air temperature and the target room temperature.Further, in step 24, the power consumed by the operation of the outsideair introduction means 6 is estimated and determined on the basis of theabove-mentioned equation (2), for example.

In step 25, the calculated power consumption of the compressor 101 andthe estimated power consumption of the operation of the outside airintroduction means 6 are compared. Further, when it is determined thatthe power consumption of the compressor 101 is larger than the powerconsumed by the operation of the outside air introduction means 6, theprocess proceeds to step 26. Furthermore, when it is determined that thepower consumption of the operation of the air-conditioning apparatus isnot larger than the power consumed by the operation of the outside airintroduction means 6 (the power consumption of the air-conditioningapparatus is equivalent to or smaller than the power consumed by theoperation of the outside air induction means 6), the process proceeds tostep 30. In step 26, outside air cooling operation is performed. On theother hand, in step 30, the compressor 101 is driven and the coolingoperation with the air-conditioning apparatus is performed, and theprocess proceeds to step 20.

In step 27, the power consumption determination means 16 calculates anddetermines the current power consumption of the outside air introductionmeans 6 on the basis of the current rotation speed of the outside airintroduction means 6 and the relationship between the current rotationspeed of the outside air introduction means 6 and the power consumption.Further, in step 28, the power consumption of the compressor 101 isestimated and determined on the basis of the current room temperature,the target room temperature, and the current outside air temperature andon the basis of the data of the room temperature, the target roomtemperature, the outside temperature, the pressure, the temperature, therotation speed, and the power consumption of the compressor 101. In step29, it is determined whether the power consumption of the outside airintroduction means 6 is equivalent to or larger than the powerconsumption of the air-conditioning apparatus. When it is determinedthat the power consumption of the outside air introduction means 6 isnot equivalent to or larger than the power consumption of theair-conditioning apparatus (the power consumption of theair-conditioning apparatus is larger), the process proceeds to step 26and outside air cooling operation is performed. On the other hand, whenit is determined that the power consumption of the outside airintroduction means 6 is equivalent to or larger than the powerconsumption of the air-conditioning apparatus, the process proceeds tostep 30. Further, in step 30, the cooling operation with theair-conditioning apparatus is performed, and the process proceeds tostep 20.

As above, according to the air conditioning system of Embodiment 3, thepower consumption determination means 16 determines the powerconsumption of the outside air introduction means 6 and the powerconsumption of the air-conditioning apparatus by measurement andestimation, directly compares each power consumption with each other,and determines whether the outside air introduction means 6 or theair-conditioning apparatus (compressor 101) is to be operated; hence,determination of energy saving operations with higher precision can bemade.

Embodiment 4

In the above-mentioned Embodiments including Embodiment 1, the targetroom temperature is set such that the target room temperature for smalloccupant number is higher than the target room temperature for largeoccupant number; however, the invention is not limited to the abovesetting and any target room temperature may be set. Further, conditionssuch as a schedule may be added.

For example, in an office and the like, in the morning and evening whenthere is heavy traffic of people entering and exiting the office, evenif the number of occupants decreases, the target room temperature may beset so as not to be increased since there is a large amount of activitygoing on, On the other hand, during the daytime when the office isoccupied by office workers working at desks, the target room temperatureis set such that the target room temperature for small occupant numberis higher than the target room temperature for large occupant number,thus achieving energy saving.

Further, for example, at an event site and the like, the target roomtemperature is set not to be changed even in the daytime. In addition,typically, since the outside air temperature in the night drops and theair conditioning load decreases, the target room temperature may be seton the basis of the number of occupants and thus achieve energy saving.

Furthermore, in the above-mentioned Embodiments including Embodiment 1,the power consumption of each of the compressor 101 and the outside airintroduction means 6 is calculated on the basis of preset data; however,a watt-hour meter may be provided measuring each power consumption, forexample.

Additionally, in the above-mentioned Embodiments including Embodiment 1,criteria for the target room temperature determination were temperaturesrelated to the detection of the room temperature detection means 9 andthe outside air temperature detection means 10; however, the inventionis not limited to the above criteria. For example, humidity detectionmeans may be provided inside/outside the air-conditioned room 4 and theenthalpy inside/outside the air-conditioned room 4 may be calculated asdata for determining the target room temperature.

Furthermore, in the above-mentioned Embodiments including Embodiment 1,the target room temperature is determined on the basis of the signalfrom the human body position detection means 5 and in correspondencewith the state of the user(s) 20 in the air-conditioned room 4. However,clocking means may be further provided that provides delay time suchthat the target room temperature is reduced and high cooling is set fora set time period when it is once determined that the user 20 hasincreased.

REFERENCE SIGNS LIST

1 outdoor unit; 2 refrigerant pipe; 3 indoor unit; 4 air-conditionedroom; 5 human body position detection means; 6 outside air introductionmeans; 7 outside air introduction duct; 8, 8 a, 8 b, 8 c, 8 d, 8 esignal line; 9 room temperature detection means; 10 outside airtemperature detection means; 11 controller; 12 target-room-temperaturedetermination means; 13 cooling-operation-method determination means; 16power consumption determination means; 20, 20 a, 20 b, 20 c, 20 d user;21, 21 a, 21 b vertically oriented output signal; 22, 22 a, 22 bhorizontally oriented output signal; 31 line representing powerconsumption when outside air introduction means 6 is driven; 32 linerepresenting power consumption when compressor 101 is driven; 101compressor; 102 four-way valve; 103 outdoor side heat exchanger; 104outdoor side fan; 301 indoor side heat exchanger; 302 indoor sideexpansion device; 303 indoor side fan; 300 indoor unit.

What is claimed is:
 1. An air conditioning system, comprising: anair-conditioning apparatus performing air conditioning of anair-conditioned space by using a refrigerant discharged by a compressor;a fan supplying air outside the air-conditioned space into theair-conditioned space; an outside air temperature sensor detecting atemperature outside the air-conditioned space; a heat source sensordetecting a heat source object in the air-conditioned space;target-room-temperature determination means determining a target roomtemperature that is a temperature target of the air-conditioned space bydetermining a user number and a variation of the user number in theair-conditioned space based on a detection of the heat source sensor;and cooling-operation-method determination means determining whether tooperate the air-conditioning apparatus or to drive the fan based on thetarget room temperature and the temperature outside the air-conditionedspace.
 2. The air conditioning system of claim 1, wherein thetarget-room-temperature determination means determines the target roomtemperature from among three or more target room temperatures that havebeen preset based on the user number and the variation of the usernumber.
 3. The air-conditioning system of claim 1, further comprisingpower consumption determination means determining a power consumption ofthe air-conditioning apparatus and a power consumption of the fan,wherein the cooling-operation-method determination means determineswhether to operate the air-conditioning apparatus or to operate the fanbased on comparison of the power consumption of the air-conditioningapparatus and the power consumption of the fan.
 4. The air conditioningsystem of claim 3, further comprising an indoor air temperature sensordetecting a temperature inside the air-conditioned space, wherein thepower consumption determination means determines, among theair-conditioning apparatus and the fan, the power consumption of theapparatus and/or the fan in operation by means of measurement, and thepower consumption determination means estimates and determines, amongthe air-conditioning apparatus and the fan, the power consumption of theapparatus and/or the fan not in operation based on the target roomtemperature, the temperature outside the air-conditioned space, and thetemperature inside the air-conditioned space.